 A new report in anesthesiology suggests that personalization is key to protecting lung function during surgery and to reducing the chance of post-operative lung collapse. Lung protective ventilation has long been linked with better outcomes for certain patients undergoing general anesthesia, but one ventilatory parameter still in need of optimization is positive end expiratory pressure, or PEEP. There's been a general lack of agreement regarding whether low or moderate levels of PEEP are more protective during surgery. The new study suggests that this lack of consensus occurs, at least in part, because PEEP isn't usually tailored to a patient's individual physiology. This conclusion was based on a randomized trial of 40 patients with healthy lungs who underwent abdominal surgery. All patients were initially anesthesized and ventilated with a PEEP of 4 cm H2O. Then they were randomized to either maintain this level of pressure or to receive a personally tailored PEEP determined through a titration protocol. In the protocol, PEEP was incrementally decreased while keeping other ventilatory parameters constant. Electrical impedance tomography signals were recorded at baseline and throughout the titration. At the end of the procedure, the recording equipment automatically calculated the percentage of over-distended and collapsed lung units for each level of pressure. The PEEP nearest the crossing of the curves representing these parameters was chosen as the optimal value. In this way, the team conducting the trial achieved a mechanical compromise where both of these outcomes were minimized. The researchers found that the optimal PEEP varied widely among patients, but determining this value did improve outcomes. Those ventilated with an individually tailored PEEP showed better intraoperative oxygenation, lower driving pressure, and a reduced incidence and severity of postoperative lung collapse. And these benefits came with minimal side effects as varying the PEEP did not cause intraoperative hemodynamic instability or a need for additional vasoactive drugs or fluids. Overall, these findings suggest the use of a standardized PEEP in patients with normal lungs may not offer the best protection against postoperative lung complications. Although larger trials are still needed to follow long-term measures of lung function, the study lays an important foundation to help enhance the safety of intraoperative ventilation.